Experimental Study On The Sulfate Corrosion-Resistance Admixture For Concrete

Sulfate attack is one of the most important problems on concrete durability, Improving the resistance of sulfate attacks is an important part of durability design of concrete structure. In general, Sulfate erosion research is divided into material level and structure level, This text proceeds with material level, a concrete sulfate corrosion-resistance admixture is developed with artificial water-hardening materialsα, natural materialsβand super mineral admixtureγ. Mechanics properties and durability of concrete with concrete sulfate corrosion-resistance admixture are also studyed.This paper includes studies as follows:1) Domestic and foreign research of resistance of sulfate attacks and the mechanism of sulfate attack.2) 20 mixes are designed based on the hydration mechanism of above mentioned 3 components. It is optimized by means of systematical research on specific surface area, setting time, expansion ratio, compressive strength ratio, corrosion resistance coefficient and expansion coefficient of 20 mixes. Through the experiments, the optimum formula is determined, which satisfies the requirements of industry standard JC/T1011-2006 regarding"Sulfate Corrosion-Resistance Admixture for Concrete.3) High performance concrete is produced with concrete sulfate corrosion-resistance admixture and parts of cement replaced by super fine slag powder or fly ash. Properties of concrete with concrete sulfate corrosion-resistance admixture, including compressive strength, the penetration resistance of chloride ions, sulfate resistance and carbonation are investigated, Prescription is further optimized by means of experiments research.4) Internal microstructure of samples are analysed by microstructure tests XRF, XRD and SEM.5) Analysis of the society and the economic benefits of sulfate corrosion-resistance admixture. The research result demonstrates that a concrete sulfate corrosion-resistance admixture with good performance is successfully developed and erosion resistance coefficient is greater than 0.85, which accords with the GradeⅠ.Compressive strength of concrete with concrete sulfate corrosion-resistance admixture is more than 80% of reference concrete, The strength ratio of concrete can be up to121%. The results reveal that the penetration resistance of chloride ions, sulfate resistance and carbonization resistance is obviously improved by addition of sulfate corrosion-resistance admixture, corrosion resistance coefficient of concrete can be up to 94% and the its anti sulfate erosion grade is KS150. Microstructure of cement stone is analysed with the permeability the sodium ion, the XRD spectrum ,SEM image of sample by XRF,XRD,SEM. Experiments indicate that production of Calcium hydroxide decrease and production of ettringite increase.